Former Panama strongman Manuel Noriega has returned home to Panama under tight security, after serving more than 20 years in prisons in the United States and France for drug trafficking and money laundering.

Noriega, military dictator 1983-1989, now faces three separate sentences for crimes committed in Panama, including the murder of critics.

The ex-strongman arrived on an Iberia flight from Paris escorted by a delegation of six foreign ministry officials, police, doctors and a prosecutor.

Journalists aboard the flight told local media that doctors had to examine Noriega for unexplained health reasons upon arrival.

Noriega's rule came to an end when US president George HW Bush ordered US troops to invade Panama on December 20, 1989, claiming it was necessary to safeguard US citizens, secure the US-built canal, battle drug trafficking and defend democracy.

US soldiers overwhelmed the Panama Defence Force, and after days on the run Noriega took refuge in the Vatican embassy.

Forces surrounded the building and blasted heavy metal music from loudspeakers for days to draw the dictator out.

Noriega finally surrendered on January 3 1990, and was immediately flown to the United States to face drug trafficking charges.

Now 77 and frail, Noriega's return reopens a painful chapter for opponents and victims of his regime as well as ordinary Panamanians who say the ex-strongman has shown no sign of remorse.

However Panama's predominantly youthful population - the average age is 27 - is more concerned with the economic rigors of everyday life, not the fate of a man who ruled the country before many of them were even born.

Jail time unclear

Awaiting Noriega is a 12-square-metre cell with two windows, a bed, a bathroom and a metal door in a prison called El Renacer, which means rebirth in Spanish, on the banks of the Panama Canal north-west of Panama City, the government said.

The government released a video of the cell, which has a small table and shelf, after accounts in the local press suggested the former dictator would be enjoying comforts including a double bed, a refrigerator, easy chairs and other furnishings.

"Inmate Noriega will be placed in an individual cell, without luxuries and in similar conditions as the rest of the detainees," the government said in a statement.

It remains uncertain exactly how long Noriega may spend behind bars, as Panamanian law allows inmates aged 70 and over to petition for house arrest.

Relatives of victims of Noriega's regime have virulently opposed applying the rule to the former dictator.

Aurelio Barria, who organised the Civic Crusade series of protests in the 1980s against the regime, called for demonstrators to come out into the streets to repudiate the former ruler and insist that he serve out his sentence in jail, not at home.

"Let him live out his old age - he will go to prison but then go home. Noriega is not the only one to blame, there were others, but he is paying for what he did," Elvia Maria Ugarte, a 46-year-old housewife, said.

At his extradition hearing in November, Noriega said he wanted to "return to Panama without hatred or resentment."

"I want to go back to Panama to prove my innocence in these procedures that were carried out in my absence and without legal assistance," he told the court.

The return of Noriega, on the CIA's payroll from 1968 to 1986 before he became an enemy of Washington, has sparked speculation over the possibility that he could reveal secrets about political figures and wealth amassed under his regime.

Panama's current president, Ricardo Martinelli, has said that he would like to know who "in one way or another has been enriched at the expense of the military and the state" during that time.

Noriega spent more than 20 years in a US jail after his overthrow in 1989 before being extradited to France in 2010, where he was convicted of money laundering.